Preparation of phosphorus halides



United States Patent Olfice 3,429,916 Patented Feb. 25, 1969 PREPARATIONOF PHOSPHORUS HALIDES Joseph W. Baker, Kirkwood, and Raymond E.Stenseth,

St. Louis, Mo., assignors to Monsanto Company, St.

Louis, Mo., a corporation of Delaware No Drawing. Filed Dec. 22, 1965,Ser. No. 515,754 US. Cl. 260-543 15 Claims Int. Cl. C07f 9/52; C09k3/28; C10m 1/48 wherein R, which can be the same or different, ishydrocarbyl of not more than 18 carbon atoms bonded to the phosphorusatom through a carbon phosphorus bond, X is halogen (Cl, Br, F and I)and n is an integer from 0 to 1, and mixtures thereof are prepared bythe process which comprises reacting an organic disulfide of the formulaRSSR with a phosphorus trihalide of the formula PX wherein each R ishydrocarbyl of not more than 18 carbon atoms and X is as defined above.The reaction of this invention can be represented by the followi'ngnon-stoichiometric expression In accordance with the above representedreaction, the process of this invention results in the concomitantproduction of organophosphonothioic dihalides [RP(S)X anddiorganophosphinothioic halides [R P(S)X]. When substantially equimolaramounts of reactants are employed, the organophosphonothioic dihalidesgenerally comprise a major amount of the product phosphorus compoundsand the diorganophosphinothioic halides a minor amount of the productphosphorus compounds. However, the ratio of diorganophosphinothioichalide to organophosphonothioic dihalide in the product phosphoruscompounds can be increased by using an excess of organic sulfidereactant.

Representative R hydrocarbon radicals for the compounds of the aboveformulae prepared by the process of this invention include by way ofexample alkyl (1 to 18 carbon atoms) such as methyl, ethyl, n-propyl,isopropyl, I

n-butyl, sec-butyl, isobutyl, tert-butyl, amyl, hexyl, heptyl, octyl,nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl and the varioushomologues and isomers of alkyl having from 1 to 18 carbon atoms;alkenyl (2 to 18 carbon atoms) such as vinyl, allyl, n-butenyl-l,n-butenyl-2, n-pentenyl-Z, n-hexenyl-Z, 2,3-dimethylbutenyl-2,n-heptenyl, n-decenyl, n-dodecenyl and the various homologues andisomers of alkenyl having 2 to 18 carbon atoms; alkynyl (3 to 18 carbonatoms) such as propargyl and the various homologues and isomers ofalkynyl having from 3 to 18 carbon atoms; cycloalkyl and alkylsubstituted cycloalkyl (3 to 18 carbon atoms) such as cyclopentyl,cyclohexyl, monoand polymethylcyclohexyl, monoand polyethylcyclohexyl,cycloheptyl and the like; cycloalkenyl and alkyl substitutedcycloalkenyl (3 to 18 carbon atoms) such as cyclopentenyl, cyclohexenyl,cycloheptenyl, monoand polyethylcyclohexenyl and the like; aryl (6 to 18carbon atoms) such as phenyl, biphenyl, naphthyl and the like; aralkyl(7 to 18 carbon atoms) such as benzyl, phenylethyl, diphenylmethyl andthe like and alkaryl (7 to 18 carbon atoms) such as tolyl, ethylphenyl,xylyl, butylphenyl, tert-butylphenyl, trimethylphenyl, diethylphenyl,methylpropylethylphenyl and the like.

The process of this invention is usually carried out with substantiallyequimolar amounts of organic disulfide and phosphorus trihalide, but anexcess of either can be used. The reaction can be carried out in theliquid or vapor phase at temperatures from about C. to about 600 C.Preferably the liquid phase reaction is carried out at temperatures fromabout C. to about 350 C. from the standpoint of optimum conversion inreasonable reaction periods. Reaction temperatures below about 100 C.can be used, but the reaction time is increased substantially at suchlower temperatures. At temperatures above about 350 C. in the liquidhase decomposition occurs and the yield of phosphonothioic andphosphinothioic compounds is substantially reduced. The vapor phasereaction is preferably carried out at temperatures from about 300 C. to600 C. The reaction can be carried out at subatmospheric, atmospheric orsuperatmospheric pressure, the pressure not being critical. The exactreaction conditions, i.e., time, temperature and pressure will dependupon the specific organic sulfide employed. The reaction can be carriedout in the presence of an inert organic medium or inert carrier gas.Suitable organic media include for example, xylene, mesitylene,decahydronaphthalene, dichlorobenzene, benzene, toluene,tetrahydronaphthalene and chlorinated biphenyls. Suitable vapor phaseinert carriers include for example nitrogen, helium, argon and methane.

Various halide catalysts can be employed in the proc ess of thisinvention. It is particularly advantageous from the standpoint ofincreased yield and less severe reaction conditions to carry out thereaction in the presence of a halide catalyst selected from the groupconsisting of (a) organic halides of the formula (R-}X wherein R ishydrocarbyl of not more than 18 carbon atoms selected from the groupconsisting of alkyl, alkenyl, alkynyl, cycloalkyl and aralkyl, X ishalogen (Cl, Br, I and F) and m is an integer from 1 to 3, (b) inorganichalides of the formula MeX wherein Me is selected from the groupconsisting of metal and NH X is halogen (Cl, Br, I and F) and v is theactual valence of Me and is an integer from 1 to 6 and (c) halogensselected from the group consisting of Q Br and I Mixtures of the abovehalide catalysts also can be employed in the process of this invention.

Representative organic halide catalysts of the formula (R-lX which can'be used in this invention include by way of example alkyl halides suchas methyl chloride, methyl iodide, methyl bromide, methyl fluoride,ethyl chloride,

ethyl iodide,

ethyl bromide,

ethyl fluoride, dichloroethane, n-propyl chloride, n-propyl bromide,isopropyl iodide, n-butyl bromide, sec-butyl iodide, tert-butyl bromide,1,3,3-trichlorobutane, 1,3,3-tribromobutane, pentyl chloride, pentylbromide,

a 3 and the straight and branched chainnonyl, decyl, undecyl, dodecyl,tr'idecyhttradecyl,'pentadecyl, hexadecyl, heptadecyl and octadecylchlorides, bromides, fluorides and iodides; alkenyl halides such as andthe various homologues and isomers of alkenyl halides having 2 to 18carbon atoms; alkynyl halides such 'as propargyl' chloride, propargylbromide, propar'gyl iodide and the various homologues and isomers ofalkynyl halides having 3 to 18 carbon atoms; cycloalkyl halides such aschlorocyclopentane, bromocyclopentane, 2,4 dichlorocyclopentane,chlorocyclohexane, bromocyclohexane, 2,4 dichlorocyclohexane, 2,4,5trichlorocyclohexane, chlorocycloheptane, 2,5-dichlorocycloheptane,2,4,S-tribromocycloheptane and the like, and aralkyl halides such asbenzyl chloride, benzyl bromide, chlorophenylethane, bromophenylethane,2,4-dichlorophenylethane, 2,4,5-trichlorophenylethane, 2,4,6tribromophenylethane, di(2,4-dichlorophenyl)methane and the like. Thepreferred organic halide catalysts of the formula (R-}X are thosewherein R is alkyl, alkenyl, alkynyl, cycloalkyl or aralkyl having notmore than 8 carbon atoms, X is chloride and m is an integer from 1 to 3.

Representative metallic halide catalysts of the formula MeX which can beused in this invention include by way of example the halides of Na, K,Ti, Ba, Al, Sb, As, Be, Bi, Cd, Ce, Co, Cu, Ga, Au, In, Fe, La, Pb, Mn,Hg, Nb, Ni, Os, Re, Se, Ag, Ta, Tl, Sn, Zn, and the like.

Specific examples of suitable inorganic halide catalysts of the formulaMeX include by way of example:

AlBr BiI GaBr PbBr AlCl CdBr GaCl KBr AlF3 ReCl G313 SnCL; SbBr SeF,AuBr TiCl, SbCl AgBr AuBr TiBr SbI AgF AuCl Till, SbCl AgI A1101, NH ISbI TaCl AuI PbCl SbI5 IHBI'a AsBr CdF- InCl MnBr AsCl Cdl Znl MnCl NbClCeCl NaCl MnI NiBr CoBr NaI HgBr NiCl CoCl NaBr HgBrI NiI C01 KCl HgClQ5136 CuBr NH Cl z ReCl CuBr Inl Hgl ASFa FCB r2 5 AsI; CuCl FeBr ReClBeBr TaBr F eCl TaCl BeCl TlCl FeCl ZnCl BeF SnBr; FeI KI BeI SnCl LaBrBaCl BiBr ZnBr LaCl NH Br BiCl CuI LaI The amount of catalyst employedis not critical. The exact amount will vary somewhat depending upon thespecific catalyst and the specific organic disulfide reactant. Thecatalyst is present in a catalytic amount, generally from about 0.0 0. ml t9 about 0.2 mol per mol of or- ..ganic. disulfide reactant.However,.lgreater ornlesser amounts can be employed. Preferably, thecatalyst is present in an amount of at least about 0.005 mol per mole oforganic disulfide reactant.

The separation of the desired phosphorus compound from the productmixture is readily accomplished by conventional means well known in theart, e.g. fractional distillation under reduced pressure, selectiveextraction, fractional distillation using a carrier gas, filmdistillation, elution or any suitable combination of these methods.

The phosphorus compounds produced by the process of this invention andnumerous uses therefor are. well known in the art. These compounds areuseful as fire retardants and rust inhibitors, and chemicalintermediates in the preparation of petroleum additives, agriculturalchemicals, organophosphorus polymers and other products of commercialinterest. For example, valuable lubricity additives for lubricating oilscan be prepared by reacting the phosphorus compounds prepared by theprocess of this invention with phenol at temperatures from about C. toabout 150 C. in the presence of an acid acceptor in accordance with thefollowing equations:

wherein R and X are as defined above.

The following examples will illustrate the invention. Parts and percentare by weight unless otherwise indicated.

EXAMPLE 1 A pressure vessel is charged with 95.1 parts of methyldisulfide and 137.4 parts of phosphorus trichloride. The vessel issealed and the reactants are heated at 275 C. for 12 hours. At the endof this time the vessel is cooled to room temperature, opened and theliquid product mixture is removed. Gas chromotographic analysis showsthat the product mixture contains 36.2 weight percentmethylphosphonothioic dichloride and 3.0 Weight percentdimethylphosphinothioic chloride. The liquid prod net is fractionatedand the methylphosphonothioic dichloride is recovered at 6070 C., 50 mm.of mercury and the dimethylphosphinothioic chloride is recovered at58-61 C., 10 mm. of mercury.

EXAMPLE 2 A reaction mixture comprising 62.8 parts of methyl disulfideand 137.4 parts of phosphorus trichloride is admitted into a U-tubeimmersed in a bath containing a heat transfer agent at a temperature ofabout 500 C. at the rate of about 4 parts per minute. A stream of drynitrogen flowing at the rate of about parts per minute is also admittedto the U-tube. The average residence time is about 10 seconds. The gasstream emerging from the U-tube is led into an ice-cooled receiver.Yields of dimethylphosphinothioic chloride and methylphosphonothioicdichloride comparable to those of Example 1 above are obtained.

Following the procedure of the foregoing examples and using theappropriate reactants the following organophosphonothioic dihaI-ides areprepared:

EXAMPLES 3-28 3ethylphosphonothioic dichloride 4-methylphosphonothioicdi'bromide' 5propylphosphon'othioic dibromide 6sec-butylphosphonothioicdichloride 7amylphosphonothidic difluoride 8-heptylphosphonothioicdichloride 9decylphosphonothioic difiuoride 10octadecylphosphonothioicdichloride 11hexy1phosphonothioic diiodide 12-methylphosphonothioic -diiodide 13allylph0sphonothioic dichloride l4-propenylphosphonothioicdichloride octenylphosphonothioic difiuoride l6butenylphosphonothioicdichloride 17-cycloheptylphosphonothioic difiuoride18-cycloheptenylphosphonothioic dichloride 19-cyclohexylphosphonothioicdichloride The embodiments of the invention in which an exclusiveproperty or privilege is claimed are defined as follows:

1. Process for the preparation of phosphorus compounds selected from thegroup consisting of compounds of the formula2'0cyclohexenylphosphonothioic dichloride 5 2lphenylphosph0nothioiodichloride SZP 22-benzylphosphonothioic dichloride23-phenylethylphosphonothioic difluoride 24-tolylphosphonothioicdichloride 10 wherein R is hydrocarbyl of not more than 18 carbon25ethylphenylphosphonothioic dichloride atoms selected from the groupconsisting of alkyl, alkenyl, 26xylylphosphonothioic dichloride alkynyl,cycloalkyl, cycloalkenyl, aryl, aralkyl and alkaryl,27trimethylphenylphosphonothioic dichloride X is selected from the groupconsisting of Cl, Br, F and 28-diethylphenylphosphonothioic dichloride In is an integer from 0 to 1, and mixtures thereof I w ic comprisereacting an organic disulfide of the for- EXAMPIJE 29 1a mula RSSR witha phosphorus trihalide of the formula A pressure vessel is charged with27 parts of methyl PX at a temperature from about 100 C. to about 600 C.disulfide, 38 parts of phosphorus trichloride, and 2.3 parts wherein Rand X are as defined above. of methyl iodide catalyst. The vessel issealed and the 2. The process of claim 1 wherein the reaction iscarreactants heated :at 260 C. for 8 hours. At the end of ried out inthe liquid phase at a temperature above about this time the vessel iscooled and the product mixture 150 C. removed. Nuclear magneticresonance spectrum analysis 3. The process of claim 1 wherein thereaction is carindicates that 48.7 mol percent of the phosphorus comriedout in the vapor phase at a temperature above about pound content of theproduct mixture is methylphospho- 300 C. nothioic dichloride and 17.5mol percent of the phos- 4. The process of claim 1 wherein the organicdisulfide phorus compound content of the product mixture is diis analkyl disulfide. methylphosphinothioic chloride. The product mixture is5. The process of claim 1 wherein the organic disulfide fractionated andthe methylphosphonothioic dichloride is aryl disulfide. is removed at60-70 C., 50 mm. of mercury, and the 6. The process of claim 1 whereinthe phosphorus tridimethylphosphinothioic chloride is recovered at 58-6130 halide is phosphorus trichloride. 0., 10 mm. of mercury. 7. Theprocess of claim 4 wherein the alkyl disulfide is methyl disulfide.EXAMPLE 30 8. The process of claim 5 wherein the aryl disulfide is Apressure vessel is charged with 27 parts of methyl phenyl disulfide.disulfide, 38 parts of phosphorus trichloride and 3 parts 9. The processof claim 1 carried out in the presence of iodine. The vessel is sealedand the reactants heated of a halide catalyst selected from the groupconsisting of at 245 C. for 8 hours. At the end of this time the vessel(a) organic halides of the formula (R'-}X wherein R' is is cooled andthe product mixture recovered. Nuclear hydrocarbyl of not more than 18carbon atoms selected magnetic resonance spectrum analysis indicatesthat 28.6 from the group consisting of alkyl, alkenyl, alkynyl, cyclomolpercent of the phosphorus compound content of the 40 alkyl and aralkyl,X is halogen and m' is an integer from product mixture ismethylphosphonothioic dichloride and 1 to 3, and (b) inorganic halidesof the formula MeX 11.4 mol percent of the phosphorus compound contentwherein Me is selected from the group consisting of metal of the productmixture is dimethylphosphinothioic chloand NH X is halogen, and v is thevalence of Me and is ride, The product mixture is fractionated and themethylan integer from 1 to 6, and (c) halogens selected from thephosphonothioic dichloride is removed at 60-70" C., 50 group consistingof C1 Br and I mm. of mercury, and the dimethylphosphinothioic chlo- 10.The process of claim 9 wherein the halide catalyst ride is recovered at58-6l C., 10 mm. of mercury. is an organic halide of the formula (R}Xwherein R is hydrocarbyl of not more than 18 carbon atoms selectedEXAMPLES 31 To from the group consisting of alkyl, alkenyl, alkynyl,cyclo- Equimolar amounts of organic disulfide and the appro 50 alkyl andaralkyl, X is halogen and m is an integer from priate phosphorustrihalide are heated at 245 C. for 8 1 to 3, hours in the presence ofthe catalysts listed in Table I 11. The process of claim 9 wherein thehalide catalyst below following the procedure of Example 30. At the isan inorganic halide of the formula MeX wherein Me end of this time, theproduct mixtures are each subjected is selected from the groupconsisting of metal and NH to NMR spectrum analysis. In all examples,amounts of X is halogen, and v is the valence of Me and is an integerorganophosphonothioic dihalide and diorganophosphinofrom 1 to 6. thioichalide comparable to those of Examples 29 and 30 12. The process ofclaim 10 wherein the organic halide are obtained. catalyst is methyliodide.

TABLE I Example PX; Organic sulfide Catalyst Amount X 31 P013 Methyldisulfide NaCl 0.1 32 P013 Ethyl disulfide KBr.-. 8E5

Propargyl disulfide 0 05 0.00 I n-Pentenyl-l disulfide PbCla 0.05Dodecyl disulfide Ethylene dibromi 0. 01 PCl Methyl disulfide TiBn 0.05PBr; do KI 0.0005 41.- PBn," .do 0. 42 P01 Phenyl disulfide 43 P13Cyclohexyl disulfide 44 P l-cyclohexenyl disulfi e 45- 46-. .0 47.2,2-dichlorodecane 0.007 48- PO15 Methyl disulfide 3chloromethyl-n-pentylene-l 0.0009 49 PO13 Cycloheptyldisulfide2-chlorocycloheptane 0.003 50 PF; Methyl disulfide ZnCh 0.01

1 Mols of catalyst per mol 0! organic sulfide reactant.

7 8 13. The process of claim 1 wherein the organic disul- 3,193,3727/1965 Regel 260-960 fide is methyl disnlfide and the phosphorustn'halide is phosphorus trichloride. FOREIGN PATENTS 14. The process ofclaim 9 wherein the organic disu1-- 5 3 10/1956 Canada fide is methyldisulfide and the halide catalyst is methyl 5 1,123,664 2/1962 Germanyiodide.

15. The process of claim 9 wherein the organic disul- LEON IT E P E fideis methyl disulfide and the halide catalyst is I Z V nmary f J. E.EVANS, Assistant Examiner.

References Cited 10 UNITED STATES PATENTS 2,682,554 6/1954 Crouch et a1260-972 25246.6; 260961, 973 3,099,132 7/1963 Condit 260972

1. PROCESS FOR THE PREPARATION OF PHOSPHORUS COMPOUNDS SELECTED FROM THEGROUP CONSISTING OF COMPOUNDS OF THE FORMULA
 9. THE PROCESS OF CLAIM 1CARRIED OUT IN THE PRESENCE OF A HALIDE CATALYST SELECTED FROM THE GROUPCONSISTING OF (A) ORGANIC HALIDES OF THE FORMULA (R''$ XM WHEREIN R'' ISHYDROCARBYL OF NOT MORE THAN 18 CARBON ATOMS SELECTED FROM THE GROUPCONSISTING OF ALKYL, ALKENYL, ALKYNYL, CYCLOALKYL AND ARALKYL, X ISHALOGEN AND M IS AN INTEGER FROM 1 TO 3, AND (B) INORGANIC HALIDES OFTHE FORMULA MEXV AND NH4, X IS HALOGEN, AND VI SI THE VALENCE OF ME ANDIS AN INTEGER FROM 1 TO 6, AND (C) HALOGENS SLECTED FROM THE GROUPCONSISTING OF CL2, BR2 AND I2.